This invention relates to piling, and more particularly to an improved plastic, such as polyvinyl chloride, vacuum resisting pile.
Piling is typically utilized as the support for a dock or pier which extends over a body of water. The dock or pier will be supported by a number of such piles which are in turn embedded into the mud or sand beneath the water. Pilings are also sunk in water for anchoring boats as well as for enclosing or isolating restricted areas in a body of water. Because the piling is sunk in water, the piling material must be resistant to water corrosion and damage, and must last for a considerable period of time despite the harmful water and marine environment. At the same time, the piling material must be strong and durable, capable of supporting a great weight and capable of retaining its rigidity and shape despite stress and weight. Although metal or concrete piling is frequently utilized for support purposes on land, in a water environment these materials are usually avoided. The concrete piling is difficult to place beneath the water and therefore it is almost impossible to utilize concrete for such purposes. Most metal materials, which are strong enough and durable enough for such purposes, are also subject to corrosion when maintained in a water environment. To avoid such corrosion, the metal would first have to be treated with expensive coatings and costly processes to make them corrosive resistant. Additionally, those metals that are not corrosive, such as brass or bronze, would be prohibitively expensive for use in a typical piling for docks and piers.
As a result, the most commonly utilized material for piling in a water environment is solid wooden poles. These poles are relatively inexpensive and yet provide the necessary rigidity, durability, water resistance, and sufficient strength for supporting docks, piers, anchoring boats, etc. The wooden poles are generally not finished, but are retained in their rough state to reduce their cost even further. In supporting a dock or pier, numerous wooden piles are required and by utilizing the rough wooden poles, the cost for the piling is reduced as much as possible.
In installing the piling into the mud or sand bed, the piling is positioned over the desired location for sinking, and then hammered into the bed using a drive hammer, sledge hammer, or other source of hammer power. In some cases, a hose is connected to the outside of the wooden pile and compressed air is introduced to the lower edge of the piling to disperse the sand or mud, thereby facilitating sinking of the piling into the bed.
Although the cost of such wood piling is relatively inexpensive, its use has created numerous problems in maintenance and has necessitated frequent replacement of the piling. One of the biggest problems associated with the solid wood piling, or other similar prior art piles, is that they tend to loosen from their bed and after a while no longer provide the firmness and secure support which is needed. With continued use, the motion of the water, the movement of boats against the piles, the vibrations of the dock, and other forces push against the piles and they tend to loosen the sand or mud bed and destroy the firm base support for the piling. In many cases, the piling will be completely loosened from their base and will actually float freely in the water providing no support at all.
An additional problem concerning prior art piles is the relationship between the pile and dock or pier. The docks are generally floating, while the piles are stationary. Thus, as the docks or piers move up and down because of rising and falling tides, they tend to pull the piling up from their bed and loosen the piles.
A further problem existing with prior art piles concerns the changing water conditions, and specifically the formation of ice during cold weather. Ice generally forms at the surface of the water. The dock is also connected to the pile at about the surface of the water. As a result, just at the junction, ice will form on the pile and firmly connect the dock or pier to the pile. This will form a solid coupling and as the dock or pier moves, it will pull up the pile from its bed. Additionally, the use of wooden piles further complicates matters since the exterior surface of the wood piles is rough, irregular, and filled with cracks and crevaces. This roughness provides an excellent surface of ice adhesion and as a result, once the ice forms even the movement of the pier against the pile can not remove or break the ice formations, where movement of the ice will pull up or loosen the pile from its bed.
The rough exterior surface of the wood piling adds other problems as well. Many forms of marine life can attach itself to this rough exterior which tends to eat away and corrode the piling material. It also attracts various types of polluting material which then adheres to the piling and creates difficulties for docking boats.
When utilizing prior art piling, and especially of the wooden pole type, the piling is generally coated with an impervious material such as Creosote or other types of tar coating in order to make it water resistant. While this material may add to the life of the piling, it tends to pollute the water and presents an environmental problem.
A further problem existing with the prior art piling, especially of the wooden pole type, concerns the sizes available. Typically, wooden poles are provided in varied sizes. However, they cannot be precut to a desired shape without losing a lot of material. As a result, piles were utilized in irregular heights, and frequently a tall pile would extend upward over adjacent shorter piles thereby creating a hazard, as well as an eyesore. Irregular heights in the prior art are also caused by a pile, after being installed, further sinking into the bed after a period of time as a result of its own weight forcing the pile downwardly.